you are right to a point sidetracker but they may be able to argue that they have a custom and practice of a certain retirement age or that there is some inherent reason why you had to be retired.
However, even then if they "retired" you they didn't make you redudant. Afterall redundancy must be impersonal.
Sounds to me like you could also take an age discrimination claim to the Equality Tribunal, on the basis that the selection of you as the person to go was based on age alone, which it probably was.
If you lose in either of these Tribunal's, you only pay your own costs, not anyone else's costs. you don't need a barrister a good experianced solicitor should do it themselves.
If not, give it a rattle yourself, you've nothing to lose.
One of the Chairpersons of the EAT is in her 80s herself, so if you got her that would be a good draw!
best of luck!